Counting detector concepts are starting to be developed in the field of computed tomography. Here, processing the high photon fluxes which occur in CT is a problem.
To this end, one detection method uses direct conversion semiconductor materials. Here, an absorbed photon creates free charges which are propelled to the electrode by way of an applied electric field so that an electrical pulse is generated. The area (and approximately also the height) of this pulse is proportional to the amount of charge and hence to the energy of the absorbed photon. Accurate scanning and digitizing of the generated electrical pulses, in particular resolving the height and number of the occurring pulses, is nontrivial.
The patent application with the reference number DE 10 2007 034 982.5, which was not published before the priority date of the present patent application, illustrates an option for increasing the robustness against a variation of the pulse width in the case of clocked signal scanning by setting the scanning frequency so high that as a result of this the scanning interval is greater than the average expected pulse width. However, this method does not achieve optimal energy resolution in the case of low photon fluxes at the detector.